DESCRIPTION: The investigator has identified a novel member of the TNF ligand family, termed LIGHT, which interacts with HVEM (herpesvirus entry mediator), formerly an orphan receptor of the TNF receptor superfamily. He advances arguments that suggest that the interaction between LIGHT and HVEM, as well as the LT-beta (LT-b) receptor, may have important physiological consequences. He intends to investigate the connection between LIGHT and lymphoid development, as well as viral pathogenesis, given that HVEM serves as a receptor for glycoprotein D of Herpes simplex virus type I.